Method for rapidly evaluating swelling property of pulp for lyocell fiber and centrifugal device

Abstract

The invention discloses a method for rapidly determining the swelling property of pulp for lyocell fibers and a centrifugal device, and relates to the field of pulping and papermaking and the field of spinning. The swelling property of the pulp for the lyocell fiber is represented by measuring the ratio of the mass of an NMMO solution retained in the pulp to the absolute dry mass of the NMMO solution after a low-concentration NMMO / dissolving pulp mixed solution is subjected to centrifugal treatment under a certain swelling condition under a certain centrifugal condition. The detection method provided by the invention is rapid, efficient and stable, the NMMO swelling properties of the dissolving pulp for different lyocell fibers can be compared by using a simple centrifugal device, the difficulty degree of the dissolving pulp for absorbing the NMMO solution to the maximum extent is reflected macroscopically, and the swelling property of the pulp in a lyocell fiber production dry process is effectively evaluated.

Description

Technical Field

[0001] The invention relates to the field of lyocell fiber manufacturing, and more particularly to a method for measuring the swelling performance of pulp for lyocell fiber and a centrifugal device. Background Art

[0002] Lyocell fiber was developed in the process of searching for alternative solvents for viscose fiber. It is a new type of regenerated cellulose fiber made from natural plant fiber and N-methylmorpholine-N-oxide (NMMO) as solvent through solvent spinning. Different from the production process of viscose fiber, the preparation of lyocell fiber is a purely physical process, which also means that the impact of pulp on its production process and product quality is far greater than that of viscose fiber. Most of the performance indicators of existing pulp for lyocell fiber have adopted the performance indicators and testing methods of viscose fiber, but with the development of lyocell fiber industrialization, the performance indicators currently used can no longer fully reflect the real performance of pulp for lyocell fiber in the actual production process.

[0003] At present, in the industrial production of lyocell fiber in China, the spinning solution preparation process can be specifically divided into wet swelling process, dry process and direct dissolution process. In the dry process, swelling performance is a very important indicator reflecting the quality of pulp. Sufficient and uniform swelling of pulp is a necessary condition for preparing spinning solution with good texture. Existing detection technologies mostly evaluate its swelling performance by measuring the thickness of pulp or directly observing the changes in the diameter of a single fiber using a polarizing microscope, but these methods cannot quickly and comprehensively evaluate the overall swelling performance of pulp for lyocell fiber.

[0004] Therefore, there is an urgent need in the art for a rapid, efficient, comprehensive and reliable method for determining the swelling properties of lyocell fiber pulp. Summary of the invention

[0005] The purpose of the present invention is to provide a rapid, simple, efficient and stable method for determining the swelling properties of pulp for lyocell fibers. The method can compare the differences in swelling properties of different dissolving pulps using simple devices and test conditions, so that production personnel can have a more comprehensive evaluation of the dissolving pulp before putting it into the lyocell fiber production process.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] First, the present invention provides a method for quickly measuring the swelling properties of lyocell fiber pulp, comprising the following process:

[0008] The swelling properties of pulp for lyocell fiber are evaluated by uniformly mixing a certain mass of dissolving pulp with a low concentration NMMO solution at a certain solid-liquid ratio and a certain temperature for a certain swelling time, and then centrifuging the mixture under certain centrifugal conditions. The mass of NMMO solution retained in the dissolving pulp is measured, and the ratio of the mass of NMMO solution to the mass of absolutely dry dissolving pulp (defined as the swelling degree) is used to evaluate the swelling properties of pulp for lyocell fiber.

[0009] Preferably, the dissolving pulp is one of softwood prehydrolyzed sulfate dissolving pulp, hardwood prehydrolyzed sulfate dissolving pulp, softwood sulfite dissolving pulp or hardwood sulfite dissolving pulp.

[0010] Preferably, the swelling solid-liquid ratio is 1% to 5% C / N, and more preferably, the swelling solid-liquid ratio is 1% C / N.

[0011] Preferably, the swelling temperature is 70-90°C, more preferably, the swelling temperature is 80°C.

[0012] Preferably, the mass fraction of NMMO in the dissolving pulp / NMMO mixed solution is 50-80wt%, and more preferably, the mass fraction of NMMO in the dissolving pulp / NMMO mixed solution is 60-70wt%.

[0013] Preferably, the swelling time is ≥20 min.

[0014] Preferably, the centrifugation conditions are determined by the following method:

[0015] After a certain mass of dissolving pulp is uniformly mixed with a low concentration NMMO solution at a certain solid-liquid ratio and a certain temperature for 20 minutes, it is transferred to a centrifugal device and centrifuged in a high-speed centrifuge under different centrifugal forces (100g to 5000g) and the same centrifugal time (30s). The ratio of the pulp mass difference before and after centrifugation to the absolute dry mass of the pulp is calculated (defined as the swelling degree), and the mass of the NMMO solution retained in the dissolving pulp after centrifugation is determined. The centrifugal conditions of this method are determined by the obtained swelling degree-centrifugal speed curve and swelling degree-centrifugal time curve. More preferably, the centrifugal conditions are 500g centrifugal speed and 30s centrifugal time.

[0016] The present invention also provides a centrifugal device for measuring the swelling properties of lyocell fiber pulp as described in the above technical scheme, comprising an inner centrifugal tube and an outer centrifugal tube that are sleeved and connected, the bottom of the inner centrifugal tube is perforated, a metal mesh is placed on the upper end of the bottom of the inner centrifugal tube, the inner centrifugal tube retains a tube cover, and the outer centrifugal tube has no tube cover.

[0017] Preferably, the inner centrifuge tube is a 5 ml PP centrifuge tube, and the outer centrifuge tube is a 10 mL PP centrifuge tube, the two fit perfectly, and a certain space is left at the bottom of the outer centrifuge tube to accommodate the NMMO solution separated from the pulp during the centrifugation process.

[0018] Preferably, the perforation size of the bottom of the inner centrifuge tube is Φ0.7mm, and there is a sieve with a diameter of 1.5mm at the upper end of the bottom of the centrifuge tube, which is made of stainless steel and has a pore size of ≤0.15mm (≥100 mesh) for filtering and centrifuging the NMMO solution free outside the pulp, thereby determining the degree of swelling of the NMMO solvent into the pulp.

[0019] It can be seen from the above technical scheme that, compared with the prior art, the present invention discloses a method and a centrifugal device for quickly determining the swelling properties of pulp for lyocell fibers, which can compare the differences in swelling properties of different dissolving pulps, quickly select dissolving pulp with excellent performance, and provide certain theoretical guidance for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 This is an overall structural diagram of a centrifugal device used for measuring swelling properties of lyocell fiber pulp according to the present invention;

[0022] Figure 2 The centrifugal force-swelling curves of four dissolving pulps (softwood prehydrolyzed kraft pulp S-PHK, softwood sulfite pulp S-AS, hardwood prehydrolyzed kraft pulp H-PHK, hardwood sulfite pulp H-AS) after swelling for 20 minutes at 1% C / N solid-liquid ratio, 60wt% NMMO, and 80℃.

[0023] Figure 3 The centrifugal force-swelling curve of softwood sulfite dissolving pulp (S-AS) after swelling for 20 minutes at different solid-liquid ratios (1% C / N, 5% C / N), 60wt% NMMO, and 80℃.

[0024] Figure 4 The centrifugal force-swelling curve of softwood sulfite dissolving pulp (S-AS) after swelling for 20 minutes at different NMMO concentrations (50wt%, 60wt% NMMO, 70wt% NMMO), 1% C / N, and 80℃.

[0025] Figure 5 These are the centrifugal force-swelling degree curves of coniferous wood sulfite dissolving pulp (S-AS) after swelling for 20 minutes at different swelling temperatures (70℃, 80℃, 90℃), 1% C / N, and 60wt% NMMO conditions. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the following embodiments, the attached Figure 1 The centrifugal device shown in the figure is used to test the swelling degree. The centrifugal device used to measure the swelling performance of lyocell fiber pulp comprises an inner centrifugal tube 1 and an outer centrifugal tube 2. The inner centrifugal tube 1 is a centrifugal tube made of 5 mL PP material, and the outer centrifugal tube 2 is a centrifugal tube made of 10 mL PP material. The inner centrifugal tube retains a tube cover 4 to prevent the solution from absorbing moisture or volatilizing, and the outer centrifugal tube has no tube cover; the bottom of the inner centrifugal tube 1 is perforated with a pore size of Φ0.7 mm, and a sieve 3 with a diameter of 1.5 mm is provided at the bottom of the inner centrifugal tube 1. The sieve 3 is made of stainless steel and has a pore size of ≤0.15 mm (≥100 mesh) for centrifugally filtering the NMMO solution free outside the pulp. The inner centrifugal tube 1 and the outer centrifugal tube 2 fit well together, and a certain space is left at the bottom of the outer centrifugal tube 2 to accommodate the NMMO solution separated from the pulp during the centrifugation process, so as to determine the degree of swelling of the NMMO solvent into the pulp. Example 1

[0028] 0.02 g of coniferous wood prehydrolyzed sulfate dissolving pulp (S-PHK), coniferous wood sulfite pulp (S-AS), hardwood prehydrolyzed sulfate dissolving pulp (H-PHK), and hardwood sulfite dissolving pulp (H-AS) were respectively taken and uniformly mixed with 2 g of 60 wt% NMMO solution at 80°C for 20 min to obtain a swollen dissolving pulp / NMMO mixed solution.

[0029] The dissolved pulp / NMMO mixed solution after swelling treatment was quickly transferred to the inner centrifuge tube of the centrifuge device, and the centrifuge tube cover was closed. Different centrifugal forces (100g-5000g) were set in a high-speed centrifuge for centrifugation. After 30s centrifugation, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 0 , accurate to 0.0001g), calculate the difference in pulp mass before and after swelling, and record its ratio to the mass of absolute dry pulp as swelling degree (%) = (MM0 -0.02) / 0.02×100, thereby obtaining the centrifugal force-swelling curves of different dissolving pulp / NMMO mixed solutions, such as Figure 2 shown.

[0030] 0.02g of softwood prehydrolyzed kraft dissolving pulp (S-PHK) was mixed with 2g of 60wt% NMMO solution at 80°C for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0031] 0.02 g of softwood sulfite pulp (S-AS) was mixed with 2 g of 60 wt% NMMO solution at 80°C for 20 min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500 g centrifugal force and 30 s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0032] 0.02 g of hardwood prehydrolyzed sulfate dissolving pulp (H-PHK) was mixed with 2 g of 60 wt% NMMO solution at 80°C for 20 min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500 g centrifugal force and 30 s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0033] 0.02 g of hardwood sulfite dissolving pulp (H-AS) was mixed with 2 g of 60 wt% NMMO solution at 80°C for 20 min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500 g centrifugal force and 30 s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1, accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0034] The results are shown in Table 1 below.

[0035] Table 1

[0036] Dissolving pulp type Pulp swelling S-PHK 355.5％ S-AS 529％ H-PHK 546％ H-AS 494％

[0037] Example 2

[0038] 0.02g and 0.1g of softwood sulfite dissolving pulp (S-AS) were taken respectively and mixed evenly with 2g of 60wt% NMMO solution at 80°C for 20min to obtain dissolving pulp / NMMO mixed solutions under different solid-liquid ratios (1% C / N, 5% C / N) after swelling.

[0039] The 1% C / N and 5% C / N dissolving pulp / NMMO mixed solutions after swelling treatment were quickly transferred to the inner centrifuge tube of the centrifuge device, and the centrifuge tube cover was closed. Different centrifugal forces (100 g to 5000 g) were set in a high-speed centrifuge for centrifugation. After 30 seconds of centrifugation, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the difference in pulp mass before and after swelling, and record its ratio to the mass of absolute dry pulp as swelling degree (%) = (MM 1 -M 0 ) / M 0 ×100, thus obtaining the centrifugal force-swelling curve of 1% C / N and 5% C / N dissolving pulp / NMMO mixed solution, such as Figure 3 shown.

[0040] 0.02 g of softwood sulfite dissolving pulp (S-AS) was mixed with 2 g of 60 wt% NMMO solution at 80°C for 20 min, and then the mixed solution was quickly transferred to the inner centrifuge tube of the centrifuge device, and the centrifuge tube cover was closed. After centrifugation in a high-speed centrifuge at 500 g centrifugal force and 30 s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0041] 0.1 g of softwood sulfite dissolving pulp (S-AS) was mixed with 2 g of 60 wt% NMMO solution at 80°C for 20 min, and then the mixed solution was quickly transferred to the inner centrifuge tube of the centrifuge device, and the centrifuge tube cover was closed. After centrifugation in a high-speed centrifuge at 500 g centrifugal force and 30 s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred).1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0042] The results are shown in Table 2 below.

[0043] Table 2

[0044] Liquid-to-solid ratio Pulp swelling 1%C / N 529％ 5% C / N 482.5％

[0045] Example 3

[0046] 2 g of 50 wt%, 60 wt%, and 70 wt% NMMO solutions were respectively mixed with 0.02 g of softwood sulfite dissolving pulp (S-AS) at 80° C. for 20 min to obtain swollen dissolving pulp / NMMO mixed solutions.

[0047] The dissolved pulp / NMMO mixed solution after swelling treatment was quickly transferred to the inner centrifuge tube of the centrifuge device, and the centrifuge tube cover was closed. Different centrifugal forces (100g-5000g) were set in a high-speed centrifuge for centrifugation. After 30s of centrifugation, the mass M of the inner centrifuge tube was weighed (the mass M0 of the inner centrifuge tube after drying should be weighed before the solution was transferred, accurate to 0.0001g), and the difference in pulp mass before and after swelling was calculated. The ratio of the difference to the mass of the absolute dry pulp was recorded as the swelling degree (%) = (MM 0 -0.02) / 0.02×100, and the centrifugal force-swelling degree curves of dissolving pulp / NMMO mixed solutions at different NMMO mass fractions were obtained, such as Figure 4 shown.

[0048] 0.02g of softwood sulfite dissolving pulp (S-AS) was mixed with 2g of 50wt% NMMO solution at 80°C for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0049] 0.02g of softwood sulfite dissolving pulp (S-AS) was mixed with 2g of 60wt% NMMO solution at 80°C for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1, accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0050] 0.02g of softwood sulfite dissolving pulp (S-AS) was mixed with 2g of 70wt% NMMO solution at 80°C for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0051] The results are shown in Table 3 below.

[0052] Table 3

[0053] NMMO concentration Pulp swelling 50wt% 493.5％ 60wt% 529％ 70wt% 608.5％

[0054] Example 4

[0055] 0.02 g of softwood sulfite dissolving pulp (S-AS) was uniformly mixed with 2 g of 60 wt% NMMO solution at 70° C., 80° C., and 90° C. for 20 min to obtain dissolving pulp / NMMO solutions swollen at different temperatures.

[0056] The dissolved pulp / NMMO mixed solution after swelling treatment was quickly transferred to the inner centrifuge tube of the centrifuge device, and the centrifuge tube cover was closed. Different centrifugal forces (100g-5000g) were set in a high-speed centrifuge for centrifugation. After 30s of centrifugation, the mass M of the inner centrifuge tube was weighed (the mass M0 of the inner centrifuge tube after drying should be weighed before the solution was transferred, accurate to 0.0001g), and the difference in pulp mass before and after swelling was calculated. The ratio of the difference to the mass of the absolute dry pulp was recorded as the swelling degree (%) = (MM 0 -0.02) / 0.02×100, and the centrifugal force-swelling degree curves of the dissolving pulp / NMMO mixed solution at different temperatures were obtained, such as Figure 5 shown.

[0057] 0.02g of softwood sulfite dissolving pulp (S-AS) was mixed with 2g of 60wt% NMMO solution at 70℃ to 80℃ for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1, accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0058] 0.02g of softwood sulfite dissolving pulp (S-AS) was mixed with 2g of 60wt% NMMO solution at 80℃ for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0059] 0.02g of softwood sulfite dissolving pulp (S-AS) was mixed with 2g of 60wt% NMMO solution at 90℃ and 80℃ for 20min to obtain a swollen dissolving pulp / NMMO mixed solution. The mixed solution was then quickly transferred to an inner centrifuge tube of a centrifuge device, the centrifuge tube cover was closed, and after centrifugation in a high-speed centrifuge at 500g centrifugal force and 30s centrifugation time, the mass M of the inner centrifuge tube was weighed (the mass M of the inner centrifuge tube after drying should be weighed before the solution is transferred). 1 , accurate to 0.0001g), calculate the pulp swelling degree under this condition.

[0060] The results are shown in Table 4 below.

[0061] Table 4

[0062] Swelling temperature Pulp swelling 70℃ 492％ 80℃ 529％ 90℃ 552％

Claims

1. A method for rapidly evaluating the swelling properties of lyocell fiber pulp, characterized in that: The swelling properties of pulp for lyocell fiber are evaluated by uniformly mixing a certain mass of dissolving pulp with a low concentration NMMO solution at a certain solid-liquid ratio and a certain temperature for a certain swelling time, and then centrifuging the mixture under certain centrifugal conditions. The mass of NMMO solution retained in the dissolving pulp is measured, and the ratio of the mass of NMMO solution to the mass of absolutely dry dissolving pulp (defined as the swelling degree) is used to evaluate the swelling properties of pulp for lyocell fiber.

2. The method for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 1, characterized in that: The dissolving pulp is one of softwood prehydrolyzed sulphate dissolving pulp, hardwood prehydrolyzed sulphate dissolving pulp, softwood sulfite dissolving pulp or hardwood sulfite dissolving pulp.

3. The method for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 1, characterized in that: The swelling solid-liquid ratio is 1% to 5% C / N.

4. The method for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 1, characterized in that: The swelling temperature is 70-90°C.

5. The method for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 1, characterized in that: The mass fraction of NMMO in the dissolving pulp / NMMO mixed solution is 50% to 80% w / w.

6. The method for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 1, characterized in that: The swelling time is ≥20 min.

7. A method for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 1, characterized in that: The centrifugation conditions were determined by the following method: After a certain mass of dissolving pulp is uniformly mixed with a low concentration NMMO solution at a certain solid-liquid ratio and a certain temperature for 20 minutes, it is transferred to a centrifugal device and centrifuged in a high-speed centrifuge at different centrifugal speeds (100g to 5000g) and different centrifugal times (30s to 20min). The ratio of the pulp mass difference before and after centrifugation to the absolute dry mass of the pulp is calculated (defined as swelling degree (%) = (M-M0) / M0×100), the mass of the NMMO solution retained in the dissolving pulp after centrifugation is determined, and the centrifugal conditions of this method are determined by the obtained swelling degree-centrifugal speed curve and swelling degree-centrifugal time curve. For the test results of the four dissolving pulps, the centrifugal condition is a centrifugal speed of 500g-1000g.

8. A centrifugal device for rapidly evaluating swelling properties of lyocell fiber pulp according to any one of claims 1 to 7, characterized in that: The invention comprises an inner centrifugal tube and an outer centrifugal tube which are sleeve-connected. The bottom of the inner centrifugal tube is perforated, a metal screen is placed on the upper end of the bottom of the inner centrifugal tube, the inner centrifugal tube is provided with a tube cover, and the outer centrifugal tube has no tube cover.

9. A centrifugal device for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 7, characterized in that: The inner centrifuge tube is a 5 ml PP centrifuge tube, and the outer centrifuge tube is a 10 mL PP centrifuge tube.

10. A centrifugal device for rapidly evaluating swelling properties of lyocell fiber pulp according to claim 7, characterized in that: The mesh size of the bottom of the inner centrifuge tube is Φ0.7 mm, and the mesh material of the upper end of the bottom of the centrifuge tube is stainless steel, with a size of Φ1.5 cm and a pore size of ≤0.15 mm (≥100 mesh).

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